Precast concrete framing construction



Aug. 3, 1954 AJAMIRIKIAN PRECAST CONCRETE FRAMING CONSTRUCTION FiledMarch 10, 1947 4 Sheets-Sheet 1 ian iri

flrsham Am A. AMIRIKIAN PRECAST CONCRETE FRAMING CONSTRUCTION FiledMarcHlO, 1947 Aug. 3, 1954 4 Sheets-Sheet 2 flrrsham I .Hmz'rik ian A.AMIRIKIAN PRECAST CONCRETE FRAMING CONSTRUCTION 4 Sheets-Sheet 3 we wayAug. 3, 1954 Filed March 10,1947

Aug. 3, 1954 A. AMlRlKlAN v PRECAST CONCRETE FRAMING CONSTRUCTION 4Sheets-Sheet 4 Filed March 10, 1947 flr'sh am Hmiriliian Patented Aug.3, 1954 UNITED STATES TENT OFFICE PRECAST CONCRETE FRAMING (Grantedunder Title 35, U. S. Code (1952),

see. 266) 4 Claims.

This invention relates to pre-cast concrete or other molded plasticmaterial construction and more especially to the construction ofsupporting structures of pre-cast concrete or other plastic moldedmaterial, comprising beams, girders, columns, frames, ribs or the likesupporting structures.

In the past the supporting structures for floors, roofs, walls and likeparts of a building or structure have been built either ofpoured-in-place concrete or of other materials such as steel, timber, ormasonry. It is the main object of this invention to provide a loadsustaining space framing construction which embodies all of theadvantages of reinforced concrete construction regarding permanency,fireproofing and lower maintenance costs, as Well as all of the benefitsof prefabrication regarding savings in material, lower costs ofproduction and speedier erection. According to the invention, I providea plurality of pre-cast preferably reinforced concrete or other moldedplastic channel-shaped or troughshaped elements which are adaptable foreasy casting with the depth or transverse extent of the webs thereofmade in conformity with any desired elevational outline of the element.

A further object of the invention is to provide a framing constructionin which the channelshaped elements are directly coupled together toform box-like hollow segments or members which are of lighter weight ascompared with solid sections of comparable strength.

Another object of the invention is to provide novel types of end jointsplice whereby a plurality of hollow segments are assembled to form abeam or girder, bent or frame, or an arch rib, or the like supportingstructural assembly possessing full continuity for the imposed loadstress path or transfer.

Other objects of the invention are the provision of hollow vertical webrib or frame members, including a vertical web frame member having anaxis disposed at an angle to an axis of another of said vertical webframe members, and the provision of a vertical web frame member havingportions of its axis at an angle to each other, and the provision of arigid frame of said vertical web frame members including a vertical webframe member having an axis disposed substantially horizontally and avertical web frame member having an axis disposed substantiallyvertically, the rigid frame vertical web structure being constructed toresist forces acting along axes substantially normal to each other.

A further object of the invention is to provide the vertical web rib orframe members and the rigid frame structure including said vertical webframe members in which the mean plane of the joint between the channelsections comprising said hollow vertical web rib or frame members isdisposed substantially vertically.

With these and other objects in view which will hereinafter appear, Ihave invented the construction and framing assembly described in thespecification and illustrated in the accompanying drawings which areexemplary of the invention.

Referring to the drawings:

Fig. 1 shows an elevational view of the left half of a two-legged rigidbent comprising a girder and two leg or column segments and twoconnecting or corner knee segments in erected condition prior to finalgrouting.

Fig. 1a is a vertical sectional view of the right half of the sameassembly after grouting, taken substantially on the lines |ala of Fig. 2and laela of Fig. 5.

Fig. 2 is a cross-section substantially on line 2-2 of Fig. 1 showingthe two channel-shaped elements and one method of fastening.

Fig. 3 shows the details of the connector assembly.

Fig. 4 shows an alternative assembly construction, especially applicableto beams and struts of small depth.

Fig. 5 shows a partial cross-section of the joint between the leg orcolumn and knee segments, substantially on the line 5-5 of Fig. 1, andline 5-5 of Fig. 6.

Fig. 6 shows the detail of the erection hinge assembly at the samejoint.

Fig. '7 is a longitudinal section of a beam or girder, continuous over aplurality of supports, constructed in accordance with this invention,and including girder segments or portions and header or T-cap segmentsor portions.

Fig. 8 is an elevational view of the splice be- Fig. 13 is alongitudinal vertical section at one of the joints of the arch ribbing,substantially on line l3-l3 of Fig. 14.

Fig. 14 is a vertical cross-section adjacent one of the joints,substantially on line i li4 of Fig. 13.

Fig. 15 is a horizontal cross-section at one of the joints,substantially on line ll5 of Fig 13.

Fig. 16 shows the connecting details at the abutments of the arch rib.

Fig. 17 is a perspective view of a framing assembly consisting of acolumn, a header or T- cap segment and two struts constructed accordingto the invention.

Fig. 18 is an enlarged perspective view of the same assembly withcomponent members separated to show the manner of the jointing.

An essential feature embodied in this invention consists of theprovision of reinforced channelshaped elements I, which arepre-fabricated or pre-cast, desirably in a horizontal position of theweb, at a suitable plant, or at the site of the construction, and which,according to the invention, are assembled in pairs by bolts 2 to formsubstantially hollow segments or members, as shown in Figs. 1 and 2. Thehollow segments thus formed are particularly adapted to sustain loadapplied against (substantially normal to) the wall formed by the channelflanges or against the ends of the hollow segments or members, and whichare thus particularly adapted to be disposed in a rigid frame or ribstructure or assembly with the channel webs of the hollow segments ormembers in substantially vertical planes and with the mean plane of thejoint between the channel elements disposed substantially vertically.The channel webs of the segments or members are desirably alwaysdisposed in a plane in which the maximum bending stress is applied.

The channel-shaped element I of the present invention has severalcharacteristic features. One of these concerns its depth or transverseWeb extent or distance between the flanges. Although in many of thehollow segments or members of the present invention the dimension indepth or transverse web distance may be constant, such as in themid-girder and leg or column segments of the bent shown in Fig. l, inothers it is varied, according to the invention, as in a straight orcurved or tapered section, such as in the straight tapered haunchedsegments over the interior supports of the girder shown in Fig. '1'.Another feature concerns the outline of the channel web in thelongitudinal direction, following a straight, curved, tapered, orangular course, as illustrated respectively by the straight segments ofthe bent in Fig. 1 and the girder in Fig. 7, the curved segments of thearch rib in Fig. 11, and the tapered, divergent and axially angularsegments of the bent or knee in Fig. 1, and of the haunch in Figs. 7 and18. These variations in depth and direction, according to the invention,preferably conform to the stress pattern of the members of the assemblyand thus assure a most economical design.

While in general the walls of the elements are continuous and solid, insome cases they may also have suitable openings 29 and 2! in the web orflanges, as in Figs. 1 and 18, for connection with another framingmember, such as a strut or column, or openings 26 and 22, as in Figs. 1and 17, for placing the joint grout or other desirably semi-liquidmoldable bonding material.

Another characteristic or feature of the present invention concerns thebolting arrangement of the structure. In order to provide a ready meansof matching a pair of channel elements, a pipe sleeve 3 is castintegrally with the element at or near each flange, and through whichsleeve the coupling bolts 2 penetrate as indicated in Figs. 2 and 3preferably with suitable end washers 2a. The pipe sleeves 3 eachdesirably having a bearing plate 4 at the inner or abutting ends,preferably welded to the sleeves 3 and which is preferably inclined, asshown. When the depth of the channel Web is too small to require twolines of bolting, a single line of bolts, placed preferably atmid-height, may be used, in which case pipe sleeves may preferably beomitted from the webs and a wood block separator 5 may be used incoupling the two channels I, as indicated in Fig. 4.

The matching edges 6 of the channel flanges are preferably chamfered toprovide a partial transfer of loading from one channel element or unitof the hollow segment onto the other by direct bearing, and also forproviding a more pleasing appearance of the rib or member in exposedpositions. The bearing plates l of the bolt receiving sleeves 3 aredisposed to conform to and seat upon the matching edges 6 of the channelflanges. However, the invention is not limited to the matching channeledges being chamfered and to the bearing plates being inclined, as it isreadily apparent that the matching edges and bearing plates may bestraight and free from any inclination, within the scope of theinvention.

The reinforcing of the channel-shaped ele ments preferably consists ofwire fabric 7, desirably in channel or trough shape, located in the weband the flanges, and longitudinal reinforcing bars 8 located in the topand bottom flanges. In addition, the webs are preferably reinforced withweb diaphragms 8 of reinforced concrete or other molded plastic materialdisposed near the ends of the channel elements or at other locationsthereon as needed by design requirements for stiffening the web of theelement during handling or under load, and also to limit and define thesplice pocket which is filled with grout or the like moldable bondingmaterial in forming the end joints between the members as hereinaftermore fully described. Reinforcing members are preferably provided in thediaphragms as indicated at 9a.

The channel elements 1 are cast or molded to desired lengths and pairedto form the hollow segments which are assembled together at their endsby means of special splicing means illustrated by Figs. 8, 10, 15 and13. In general, the splices are located at points of inflection, thatis, at zones of minimum flexural stress. With the arrangement accordingto the invention, a structure such as a frame or rib is comprised of orsubdivided into a series of component segments or members, as described,shaped in elevational View as a rectangle, a trapezoid, a circular orarcuate segment, an L or a T. The forms of splicing means indicated inFigs. 8 and 10 are applicable for end splices between two segmentspositioned substantially horizontally as indicated in Figs. 1, '7, l7and 18. For this purpose the ends of the webs of each of the abuttinghollow segments are preferably so formed as to provide a longitudinalseat or step I! desirably with an adjoining inclined surface it], thusproviding a temporary seat at the steps H for the comple mentaryadjacent segments during assembly and erection, and also providingaccessibility at the wedge-shaped spaces formed between the in ned suface '0 a d. h nds of th m mentary segments, for splicing thereinforcing bars 8 which project from the ends of the segments and forcompleting the joint. The bars 8 may desirably be welded togetherdirectly by either lapped .or butt welding 12, or indirectly by means ofa splice plate or bar 25, or by means of a rod such as is shown in Fig.15, after which the wedge-shaped gap is closed by cement mortar or thelike applied within the splice pocket. As an alternative to the weldedarrangement, the projecting rodsB may be anchored by looping into thesplice pocket between the ends of the hollow segments, and then fillingthe splice pocket by cement mortar, as indicated in Fig. 10. The websadjacent the step joint H are preferably provided with hook barreinforcements l3, as indicated in Figs. 3 and 9.

When using th welded arrangement, in order to reduce the dead weight ofthe splice fill, in some Qases it may be desirable to confine the groutfill only to webs and flanges of the spliced channels. This can beaccomplished by placing a suitable form assembly within the pocket andin contact with the inside faces of the respective webs and flanges andby applying pressure grout or the like to form the desired closure onall four faces of the joint.

In the case of splices between segments positioned vertically or on aslope, such as the joints in the legs of the bent shown in Fig. 1 andthe joints of the arch rib shown in Fig. 11, the detail of Figs. 5, 13,14 and 15 may desirably be used. This consists of erection hinges castin the webs of abutting hollow segments and composed of semi-cylindricalmembers [4 and [5, one cast in each of the abutting segment webs, a baseplate 16 and anchorage bars I! as shown in Fig. 6. The ends of the websof the segments having the erection hinge mem, bers cast therein, arepreferably extended beyond the flanges, as indicated in Figs. 1, 13 and16. The reinforcing bars 8 project from the flanges and anchor into thejoint PQQliet I9 desirably by lapping as in Figs. 1 and 5 or byadditional splice bar as in Figs. 13 to 15, the said pocket then beingfilled with cement grout or the like bonding material, as indicated inFigs. 1, 5, 13, 14, 15 and 16, suitable exterior forms being employed asneeded.

A similar joint is also utilized at the abutments of the arch rib asshown in Fig. 16.

The assembly of a pro-cast concrete supporting structure according tothe invention, such as a hollow ribbing or framing structure, isaccomplished by assembling together the two channel elements of eachsegment or member of the structure, erecting the segments or members,with the webs substantially vertical, into position to form thestructure, such as a rigid frame or rib support, and joining the membersor segments together by the splicing means to complete the assembly ofthe framing structure. It is apparent that the structure according tothe invention involves the hollow vertical web rib or frame members,including a vertical web frame. member having an axis disposed at anangle to an axis of another of said vertical web frame members, andinvolves a said vertical web frame member having portions of its axis atan angle to each other. The structure according to the invention alsoinvolves a rigid frame of said vertical web frame members including amember having an axis disposed substantially horizontally and a verticalweb frame member having an axis disposed substantially vertically, saidrig-id frame vertical web struc: ture being constructed to resist forcesafiting along axes substantially normal to each other. Suitable meanssuch as hoists, and erection braces and props, as required, are employedin erection of the segments, it being apparent that a desirable,erection procedure comprises erection of the column segments, the headerTs or Ls, the struts, and the girders, and thereafter making the splicesbetween them as described, in the case of a structure such asillustrated in Figs. 1 and 7, or the like. A similar procedure isfollowed in the caseof an arch r-ib as illustrated in connection withFig. 11. some joints may be omitted by making segments on e The columnsegments are suitably secured to the floor by means of floor stubs orpedestals or column recesses, as indicated, desirably provided withupwardly projecting reinforcing received within the hollow column memberand secured by concrete or the like filling and bonding materialintroduced through a suitable opening 26 in a side wall of the columnmember or segment, as indicated in Fig. 1a.

The connections of the columns and/or struts to a header or T-cap orknee segment are con-. veniently made by anchorage of the projectingreinforcing of the connected elements into the joint pockets, asindicated in Figs. 17 and 18. For this purpose suitable epenings 20 andZ! are provided, respectively, in the web and in the wall formed by theflanges of the header and knee segments for the passage of theprojecting reinforcing 23 of the struts and columns, after which thejoint pocket I9 is filled with grout or the like through a hole 22 inthe top flange, as shown in Fig. 17. The bottom ledge 24 of the opening29 in the web serves as a temporary erection seat for the bottom flangeof the strut, which strut preferably will extend to the inner face ofthe web, while the rein-. forcing 23 will project into the pocket H) tofurnish the desired anchorage. In the case of the column connection, theopening 2| in the wall formed by the flanges is so proportioned thatwhile it allows passage for the reinforcing 23 of the column, it ispreferably made smaller than the column section in order that the lowerwall formed by the flanges of the header or T-.- cap may seat on theupper edges of the column and thus facilitate theassembly and erection.

It will be apparent that various changes and modifications may be madein the structural embodiments of the invention, without departing fromthe spirit and scope of the invention, as to which reference is made tothe appended claims.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

I claim:

1. A substantially hollow structural framing support member comprising apair of complementary pro-cast framing support channel elements eachincluding a web and flanges adjoining the edges of the web, saidpre-cast framing support channel elements of said hollow framing supportmember being secured together with edge faces of their flanges facingeach other, the said webs of said pre-cast framing support channelelements constituting opposite web side walls of said hollow structuralframing support member, an end of said substantially hollow structuralframing support member being provided with a structure for splicingcomprising corresponding end seat portions formed in the ends of saidopposite web side walls of said hollow member, said corresponding endseat portions extending longitudinally inwardly of the ends of saidopposite web side walls, and corresponding inclined end portions of saidopposite web side walls adjoining and inclining away from the innerextremities of said longitudinal end seat portions and joining an endface of the adjacent flange which is correspondingly shortened, saidpre-cast framing support channel elements each having a diaphragmextending transversely thereof near to but inwardly of the said endsplicing structure of said substantially hollow member and having anedge facing outwardly of the channel, corresponding transvers diaphragmsof said pre-cast framing support channel elements being in alignmentwith their outwardly facing edges facing each other and constituting adiaphragm wall of said hollow structural framing support member near tobut inwardly of the said end splicing structure of said substantiallyhollow member to limit and define a splice pocket in said end of saidmember.

2. In a structural framing assembly comprising a plurality of structuralframing support members, with adjoining ends of said members securedtogether, each of said plurality of structural framing support membersbeing of substantially hollow form and each comprising a pair ofcomplementary pre-cast structural framing support channel elementssecured together with the edge faces of their flanges facing each other,the webs of said pre-oast structural framing support channel elementsconstituting opposite web side walls of said hollow framing supportmembers, said opposite web side walls being disposed verticallythroughout the structural framing assembly, corresponding end seatportions formed in the ends of the said opposite vertical web side wallsof each of a pair of endwise adjoining hollow framing support members,said end seat portions extending substantially longitudinally inwardlyof the ends of the vertical web side walls, the longitudinal end seatportions of each of said pair of hollow members being disposed inseating engagement with those of the other, each of said pair of hollowmembers having corresponding inclined end portions of the vertical webside walls thereof adjoining and inclining away from the inner eXtremities of the said longitudinal end seat portions thereof and joiningthe end faces of the adjacent flanges thereof which are correspondinglyshortened, thereby providing a wedge shaped space between the saidinclined end portions of the vertical web side walls and the ends of thevertical web side walls of the complementary hollow member of said pair,said wedge shaped spaces being disposed one at either side of the saidlongitudinal seat of said pair of hollow members, and bonding materialfilling said spaces and extending within the ends of said pair ofendwise adjoining hollow members.

3. In a structural framing assembly according to claim 2, said pair ofendwise adjoining hollow framing support members each having a diaphragmwall extending transversely thereof near to but inwardly of the end ofthe member and defining a splice pocket and providing an abuttingdiaphragm wall for said bonding material.

4. In a structural framing assembly according to claim 2, reinforcingmeans extending from the ends of said pair of endwise adjoining hollowframing support members and extending into the bonding material in saidspaces.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 798,486 Aylett Aug. 29, 1905 1,083,876 Craig Jan, 6, 19141,182,872 Darrow May 9, 1916 1,734,392 Moore Nov. 5, 1929 1,757,077Eiserloh May 6, 1930 2,413,562 Henderson Dec. 31, 1946 FOREIGN PATENTSNumber Country Date 325,505 France 1902 71,429 Switzerland 1916 159,066Great Britain Feb. 24, 1921 640,518 France 1928 277,038 Italy 1930299,903 Italy 1932 556,103 Great Britain 1944 562,698 Great Britain 1944566,510 Great Britain Jan, 2, 1945

